1. Field of the Invention
The present invention relates to a sports boot, especially a gliding sports boot, or a boot for any other sport requiring the transmission of special forces, and including, in its manufacture, at least molding one of its elements. Gliding sports especially include alpine skiing, mountain skiing or cross-country skiing. snowboarding, back-country skiing, as well as ice skating and roller skating.
2. Description of Background and Relevant Information
It is widely known to manufacture a sports boot by molding plastic material for all of its components. In general, such boots are constituted of a limited number of elements; only those elements intended to move relative to one another are made distinct from one another. This method, which has been very much used for manufacturing boots for alpine ski and roller skates, among others, is very costly, because it requires molds to be made, and is not very adaptable, because the rigidity of the boot remains identical at every point thereof.
To manufacture a boot whose rigidity is not identical at every point thereof, it was first thought to vary the shell thickness. However, in order to obtain a satisfactory rigidity gradient with this method, it is necessary to use a relatively flexible material and mold it with excessive thickness in the areas where maximum rigidity is sought.
Due to these excessive thicknesses, the boots made by this method are heavy during use. Another solution consists in performing a dual-material molding, but this technique remains expensive and complicated. Moreover, the two materials that are then molded simultaneously must have relatively close chemical and physical properties, which reduces the possible rigidity gradient.
In mountain skiing, or cross-country skiing, the requirement for foot movement, in the conventional technique, and the least force transmission are such that boots are generally more flexible, and that conventional techniques, i.e., assembly by adhesive ;bonding and stitching, are primarily used during their manufacture. However, this is no longer true for the boots adapted for the practice of skating step, for which foot movement of the type carried out in the conventional technique is no longer necessary. Thus, in order for a cross-country ski boot to be efficient, some of its elements, especially the heel stiffener, must be rigid. The problem of incorporating a rigid element within a flexible structure then arises.
Two types of constructions are currently used in the manufacture of boots for roller skates: the rigid construction and the flexible construction. The rigid construction derives from the construction of alpine ski boots; a flexible liner is maintained in a rigid shell.
With such a construction, each renewed line of skates requires a number of new molds to be made, even if the changes are only aesthetic.
The flexible construction derives from the construction of cross-country ski boots.
With such a construction, it is very difficult to envision a complete line of skates, i.e., ranging from models for beginners to models for experts, while retaining the maximum of common elements.
Both of these two constructions render very costly any changes made to a line of skates.
An object of the present invention is to overcome the aforementioned disadvantages. More particularly, an object of the invention is to provide a sport boot, especially for skiing or skating, whose rigidity is not constant at every point thereof, and whose structure facilitates the changes to be made to the line.
The boot according to the invention includes at least three distinctive portions. Specifically, the boot has a rigid sole, an external upper attached to this sole, and a removable, or irremovable independent liner. The external upper has a first rigid and non-flexible portion. This first portion is attached to the sole or is an integral part thereof; it has at least one heel stiffener. The external upper also has a second portion that is less rigid than that of the first portion and less flexible than a third portion, and is attached to the first portion and/or to the sole. The external upper further has a flexible third portion attached to the second portion.
The arrangement of the three portions of the external upper, with respect to one another, is such that, except the zones that are necessary for their attachment, they are not superimposed, which allows a real rigidity gradient, from the most rigid first portion to the flexible third portion.
Preferably, the second portion has a vamp at the front of the boot, and a collar in the area of the ankle; the vamp can be attached by any permanent or non-permanent attachment members or mechanism, to the first portion and/or to the sole. Preferably, the attachment members used include rivets or screws. In the case where the attachment members are screws, they allow the vamp to be disassembled, then reassembled on the first portion and/or on the sole.
The third portion has one or more portions that are essentially attached to the second portion by any attachment members of mechanism. Preferably, the third portion is attached to the second portion by detachable or non-detachable attachment mechanism(s), such as adhesives or stitching, adapted to the flexible materials.
The difference in rigidity and flexibility between the first portion and the third portion is substantial.
The second portion, while having a rigidity and flexibility comprised between that of the first and third portion, can take a plurality of values of rigidity and flexibility. Therefore, by retaining numerous common elements, one can design a line of boots, including boots having a firm foot retention, boots with flexible retention and all intermediate levels of retention. In particular, the first rigid portion can be kept as common to all models in the line by only replacing the second and third portions, thereby substantially reducing the manufacturing costs of the necessary molds.
The third portion occupies a substantial portion of the surface of the upper located on the top of the foot. The replacement of the first and second portions makes it possible to change the external aspect of the boot. Furthermore, this element can be molded on the flat, i.e., without giving it the shape which it will assume once it has been assembled. This third portion can also be obtained by cutting large sheets of plastic material or fabric.
The means for tightening the boot are arranged on one of the three portions. Preferably, these means have a lace system arranged on the third and/or second portion, allowing to adjust the fit of the boot to the user""s foot. They also have a strap system attached directly or indirectly to the collar and ensuring the tightening of the lower part of the user""s leg. They can also have a strap system attached to the stiffener or to the vamp and ensuring the retention of the heel at the bottom of the boot.
One of the advantages of the invention consists in optimizing the compromise between the retention of the foot, on the one hand, and its comfort, on the other hand. In the zones where retention is necessary, such as in the heel zone, for example, the external upper is equivalent to a shell-type rigid upper. On the other hand, in the zones where an adjustment of the upper to the user""s foot occurs, i.e., on the top of the foot, among others, and where comfort is desirable, one benefits from the advantages of a flexible external upper.
The construction of a sports boot according to the invention therefore offers, at low cost, a wide variety of embodiments, namely, boots having numerous common elements, or using the same molds but having their own designs, and boots whose elements are made in the same molds but have different characteristics in terms of retention and comfort.
In the case of skating, one can thus provide a line including skates for experts having a maximum of flexible elements, as well as skates for beginners in which the more rigid elements prevail, without the costly manufacture of numerous molds.